The invention relates to an electrode material for use in a storage battery half-cell in which a suspension of particles of an active material is able to circulate. Such an electrode material or current collector is generally known and is described, for example, in the Dutch Application 7800921. In the description and claims which follow below, electrode and current collector are understood to mean the same, i.e. an electrically conducting material which does not itself participate actively in the electrochemical reactions which occur in the half-cell in which the material concerned is placed. In said publication, a zinc/air storage battery is described in which the zinc half-cell contains, as electrolyte, a circulating suspension of zinc particles in an alkaline liquid and in which the use of a metal anode collector with a passivating layer is described. This said zinc suspension/air system is composed in general of a separate charging and discharging cell. For this purpose, the Zn suspension can be pumped from one cell to the other cell. During the discharging of a previously charged-up zinc/air storage battery, zinc in the zinc suspension half-cell is converted into zincate in accordance with the following equation: ##STR1##
The zincate ions formed during the discharging are converted into zinc particles again during the charging-up operation. During charging-up in the charging cell, zinc will settle in the form of a particulate precipitate on the current collector used and as a rule adhere thereto, unless the metals mentioned in the Dutch Application 7800921 are used in a passivated state. It is the intention that the precipitated zinc is again present in suspension form when the storage battery is being operated and therefore easily breaks loose of the current collector.
In the case of materials normally used, such as, for example, nickel, such adhesion easily occurs and the resuspension of the zinc precipitate is considerably hampered.
The use of current collector materials such as Mg and certain of the groups 3b, 4b, 5b and 6b of the periodic system of elements, however, sometimes gives rise to problems if the hydroxide layer becomes too thick and therefore exhibits too great an electrical resistance, as described in the patent application previously mentioned.